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Utah Welcome Sign

Utah Welcome Sign

The initial discovery of chemical markers for chocolate on potsherds from Chaco Canyon in 2009 was a hugely significant development in understanding Chaco. The evidence for the presence of chocolate, a Mesoamerican product that couldn’t possibly have been locally grown and is very unlikely to have been gradually traded northward through a series of intermediaries, gave a huge boost to the “Mexicanist” school of thought about Chaco, which holds that many of the unusual aspects of the Chaco system are due to influence from Mesoamerica.

The initial study only involved a few sherds, though, and understanding the exact role of chocolate at Chaco and its implications for Mexican contact needs a much deeper understanding of where and when cacao was present in the ancient Southwest. Thus, soon after the initial discovery further research by a different set of researchers (using somewhat different methods) began to test other pots from Chaco and elsewhere. They did find further evidence that at least some of the famous cylinder jars from Chaco were used in the consumption of chocolate, but they also found traces of cacao in vessels of similar form from the later Classic Hohokam period in southern Arizona, and, most surprisingly, also in vessels from the “small-house sites” at Chaco and elsewhere that are thought to have housed the lower classes of Chacoan society. The previous evidence for chocolate came from distinctive vessels at the “great houses” that are the hallmark of the Chaco system and seem to have been used by elites (though exactly what they used them for remains unclear and controversial). This is exactly the kind of setting where it would be unsurprising to find unusual, exotic things, and indeed the great houses clearly contained many such things in addition to the chocolate. Finding this sort of exotic foodstuff in more mundane pots at the small houses implies that it may have been more widely accessible than previously thought, which has important implications for understanding the nature of the Chaco system.

Well, now things have become even more complicated. The same researchers who did that follow-up study have done another, this time looking at a much earlier period and a different part of the Southwest. They used their same techniques to test for the presence of chocolate in pottery at Alkali Ridge Site 13 in southeastern Utah, a very important early village site dating to the eighth century AD. Site 13 was one of the earliest large villages established in the northern Southwest during the Pueblo I period, and its architecture shows some striking parallels to later Pueblo I villages such as McPhee Village in the Dolores, Colorado area, as well as to some of the early great houses at Chaco and elsewhere that developed even later. The early Pueblo I period in southern Utah is also associated with the introduction of a new type of pottery, San Juan Red Ware, which was widely traded from an apparently rather restricted production area and probably used for ceremonial purposes of some sort. In addition to being a different color from the more common gray and white pottery of the area, San Juan Red Ware also featured a distinctive design system in its decoration, one without obvious local antecedents. Combined with the distinctive architecture, this has led some archaeologists to posit that there was a migration into southern Utah during early Pueblo I from somewhere to the south, bringing these distinctive traits.

In that context, looking for cacao makes sense, as that would be a clear sign of ties to the south and cultural distinctiveness. Dorothy Washburn, who was the lead author on both this and the previous study,  has actually written mainly on design style in ceramics and other handicrafts, focusing on symmetry patterns. Based on the changes she has found in these patterns, she has argued for a very strong Mexicanist interpretation of Chaco, involving actual migration of people from far to the south bringing a distinctive pottery decoration style. She seems to have a similar view about Alkali Ridge, for similar reasons.

In any case, the study found that there was in fact evidence for cacao on several of the vessels found at Site 13, including some (but not all) of the redware ones. The conclusions, understandably, focus on the association between the new ceramic design system and the use of chocolate, but in fact the redware vessels don’t seem to be much more likely to have evidence of chocolate use than the other ones that were tested. It’s quite possible that San Juan Red Ware was associated with consumption of chocolate specifically, but it seems that other types of pottery were also used for chocolate-related purposes.

This is all very interesting, but it’s also confusing and hard to interpret, in a way that the authors of this paper don’t really address. Back when it seemed like chocolate was limited to cylinder vessels at Chaco great houses, that was easy to interpret: chocolate, like many other exotic goods found at these sites, was part of an extensive trading systems for elite goods, probably used for ritual purposes, which the elites of Chaco participated in (and perhaps dominated and directed). Finding it in the Hohokam vessels implied a similar system operating among elites at Classic Hohokam sites, which is consistent with some interpretations of Classic Hohokam society, plus the Hohokam in general show lots of evidence of contact with Mesoamerica in general so the presence of chocolate is much less surprising there than it was at Chaco. Finding it in the small houses at Chaco complicated the story somewhat and implied that the chocolate imported to Chaco wasn’t as restricted as had been thought, but since it was already known to be present at the great houses it’s not too surprising that the contemporaneous small houses had it too.

Alkali Ridge, though, is much earlier and much further north than any of these other sites. Getting chocolate there in significant quantities would have required a pretty elaborate and robust supply chain over a very long distance, much of which was inhabited by societies that are not generally considered to have been capable of this kind of long-distance coordination. Checking some of those intermediate areas (especially the Hohokam region) to see if they too had chocolate this early is necessary to understand the logistics of this.

There’s also the question of time. We now have evidence of chocolate from Utah in the eighth century, New Mexico (and to a lesser extent Colorado and Arizona) in the eleventh, and Arizona in the fourteenth. There are some big gaps there that need to be filled in to determine if these are three snapshots of a long-term and continuous tradition of chocolate consumption in the Southwest (which would have important implications about trade networks and relations with Mexico) or three separate episodes of chocolate being introduced from the south, possibly through population movement (which would have important implications for regional culture history in general). I think the most important place to look for evidence of continuity between Alkali Ridge and Chaco is in the large late Pueblo I villages in southwestern Colorado, especially the Dolores-area ones like McPhee Village. These sites have apparent connections to both earlier villages like Site 13 and later developments at Chaco. If they also reveal evidence for chocolate use, that would be a strong indication of continuity. The most important places to check for continuity between Chaco and the Classic Hohokam would probably be the Pueblo III communities in east-central Arizona, which again show connections in both directions. Both of these sets of sites are among the best-studied in the Southwest and there should be plenty of pots available for these analyses.

Finally, there is a methodological issue here. It’s possible that these tests aren’t actually detecting chocolate at all, but something else. The authors of the recent paper noted this possibility and looked into whether there are any plants native to the Southwest that might have chemical profiles similar to cacao that would throw off the analysis. They didn’t find any, but they note that many plants have not been analyzed in this way and it’s possible there is a different plant that is showing up in these analyses instead. Another possibility is that there is something about their method itself that is leading to false positives. It’s noteworthy that they have been finding much more extensive evidence of chocolate than the team, led by Patricia Crown and Jeffrey Hurst, that did the initial Chaco study found. That team hasn’t published any more about chocolate at Chaco since then, but I hear Crown was able to do some re-excavation in Room 28 at Pueblo Bonito this summer so there may be more from her on this in the future. Ideally I’d like to see a test of both methods on the same vessels to see how they match up.

The ultimate message here is that even important discoveries, like chocolate at Chaco, require many further studies and refinements to interpret properly. We’re nowhere near a full understanding of the true role of chocolate at Chaco or any other site in the prehistoric Southwest, but every study gets us closer.
ResearchBlogging.org
Washburn DK, Washburn WN, & Shipkova PA (2013). Cacao consumption during the 8th century at Alkali Ridge, southeastern Utah Journal of Archaeological Science, 40, 2007-2013 DOI: 10.1016/j.jas.2012.12.017

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Junction of Alaska State Highways 1 and 2, Tok, Alaska

I’ve been reading about Alaska a lot mostly, trying to get a handle on this very complicated place where I now live.  Archaeologically, it’s fantastically complicated and not very well understood.  I’ve been meaning to do some blogging about Alaskan archaeology, but I feel like I still don’t have a very good grasp of it except at an extremely superficial level.  Unlike with the Southwest, however, that’s probably still more than virtually anyone else knows about it, so I’ll probably be doing some posts on it in the near future.  I still haven’t fully settled on whether to start a new blog or just use this one, but any near-term stuff I’ll probably just stick here.

One of the things I’m realizing is that there’s a major disconnect between the archaeological evidence known from Alaska and the role Alaska plays in a number of larger archaeological questions.  Alaska is the presumed starting point for (at least) three very important migrations that defined the cultural history of the entire Western Hemisphere, but so far the archaeological record within the state has shed virtually no light on two of them, and relatively little on the third.  Indeed, it has even been proposed that archaeological research in Alaska has been overly driven by these bigger questions, and that it would be better to try to understand it in its own terms first before trying to tackle them.

The first of these migration is, of course, the initial peopling of the Americas in the Late Pleistocene.  I’ve written before about my belief that this initial migration from Asia doesn’t matter when looking at much later developments such as those at Chaco Canyon, and I still believe that, but it is still an important issue in its own right.  Recent research in various places has increasingly indicated that the Clovis culture of around 13,000 years ago was not the direct result of the earliest migration into the Americas, but it is still the case that any migrations during the Pleistocene (and it’s increasingly looking like there were at least two) almost certainly would have had to go through Alaska.  Unfortunately, despite several decades of looking, no sites have yet been found in Alaska itself that can plausibly be taken to reflect the first immigrants into North America from Asia.  An increasing number of early sites have been identified in the past twenty years, but these are all still too late to represent a population ancestral to Clovis or any of the other early cultures found further south.  Part of the problem here is that preservation conditions for archaeological sites in most of Alaska are atrocious, and in many areas even finding early sites is extremely difficult.  The fact that the state is huge and sparsely populated also means that very little of it has even been surveyed for sites, although that is starting to change a bit with some recent efforts.  Still, we have a long way to go before archaeology within Alaska can shed much meaningful light on the issue of the peopling of the Americas.  I’ll definitely have some more in-depth discussion of this, probably fairly soon.

The second of the migrations I mentioned above is that of speakers of Athapaskan languages to the south, ultimately as far as the Southwestern US and the extreme north of Mexico.  As I’ve mentioned before, it’s long been quite obvious that Navajo and the various Apache languages, as well as several languages of California and Oregon coasts, are closely related to a larger number of languages in Alaska and northwestern Canada.  The distribution of the languages, as well as some internal evidence in the southern branch, strongly suggests that the direction of the migration that led to this situation was north-to-south, and similar evidence similarly suggests that the start point was somewhere in what is now Alaska.  Despite the enormous distance over which Athapaskan languages are now spread, the greatest diversity of the languages grammatically is actually found within Alaska.  That is, some Alaskan languages are more closely related to Navajo than they are to other Athapaskan languages in Alaska.  While this is all clear linguistically, tracing the actual migration archaeologically has been enormously difficult at both ends.  Athapaskan archaeology in Alaska in particular is remarkably poorly understood compared to the archaeology of Eskimo groups, due in part to the fact that Athapaskans have mostly occupied the interior areas that are harder to investigate than the primarily Eskimo coastal areas.  I’ll definitely be writing more about this issue from both linguistic and archaeological perspectives, and given the obvious Southwestern connection a lot of that discussion will probably be on this blog even if I start another one.

The third migration, and by far the best understood, is that of so-called Thule peoples from northwestern Alaska eastward across the Arctic as far as Greenland.  The descendants of these migrants are the modern Inuit of Arctic Canada and Greenland, who have close linguistic and cultural connections to the Inupiat of northern Alaska.  While the exact time this migration took place is not totally clear, dates of around AD 1000 to 1200 are usually suggested, which makes it roughly contemporaneous with the major events at Chaco.  Unlike with the other two migrations, the starting point for this one has been fairly well established through extensive archaeological work along the Alaska coast that has defined a series of archaeological cultures leading up to the Thule culture.  Eskimo archaeology has been the main focus of most research in Alaska to date, and it shows in the level of knowledge about these cultures compared to the much more obscure Athapaskan and early cultures.  Still, however, many aspects of Alaskan Eskimo cultures are poorly understood.  (I am aware that the term “Eskimo” is generally avoided in Canada in favor of “Inuit.”  This is not the case in Alaska, where “Eskimo” is widely used and “Inuit” is not considered appropriate in most contexts.  The terms are not synonymous, and in the Alaskan context I think “Eskimo” is probably the best general term to use despite the very real problems with it.  I’ll definitely be discussing this issue further in the future.)

These are the big issues that make the archaeology of Alaska important to New World archaeology in general, and they have been the main impetus for much of the archaeological research done in Alaska to date.  The results have been stubbornly unhelpful in addressing most of them, however, while at the same time bringing to light the unexpectedly diverse and complex prehistory of Alaska itself.  It has long been much more than a corridor or starting point for people going elsewhere.  While the stories of the migrations from Alaska are definitely interesting and important, the ones that took place entirely within Alaska are interesting and important too.

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Sign at State of New Mexico Archives Building, Santa Fe, New Mexico

Several months ago Steve Lekson sent me a review copy of his latest book, A History of the Ancient Southwest.  I recently got around to reading it, and it’s very good.  The importance as well as the idiosyncratic nature of this book begins with its title.  While the title sounds generic, it’s actually carefully chosen and worded, and in a subtle way it expresses the unusual approach Lekson takes to Southwestern archaeology, not just in this book but in many of his other recent publications.

The crucial thing about the title, and about the book, is the word “history.”  This book is both an attempt to tell the story of what happened in the ancient Southwest, and thus a “history” of the Southwest in ancient times of the sort an historian might write, and a parallel attempt to tell the story of the development of Southwestern archaeology as a (sub)discipline, i.e., a history of “the ancient Southwest” as an idea and of the ways that idea has been studied and interpreted over time.  The title also refers, quite deliberately, to a book with the same title that Harold Gladwin published in 1957.  Gladwin’s a fascinating character, as is Lekson himself in his own way, but in this context the most important thing about him is his fondness for synthesizing archaeological data and presenting it as an accessible narrative.  Lekson is seeking to do the same thing in this book, and he mostly succeeds.  This is a more impressive accomplishment than it sounds, because summarizing the entire prehistory of the Southwest in narrative form is an astonishingly ambitious project, and there’s a reason no one else has tried to do it since Gladwin.  Furthermore, Lekson adds on top of this enormously difficult task the additional task of adding a parallel intellectual history of Southwestern archaeology.  And yet, like I say, he mostly succeeds in this near-impossible task.

How does he do it?  Partly by limiting his narrative to the highlights of both stories, which admittedly makes it seem a bit thin at times.  This is largely countered by his the very extensive notes, where he relegates most of the in-depth argumentation over scholarly minutiae that would get in the way of the overall story.  And when I say “extensive,” I mean it; this is a book with 250 pages of text followed by 100 pages of notes.  I haven’t read through all the notes in detail, but they’re a mix of perfunctory citations for statements in the text and really long and detailed discussions of various archaeological points of contention and Lekson’s positions on them.

Part of the reason for this shoving of so much into the notes is to make the text more accessible.  The book is aimed both at professional Southwestern archaeologists and at popular audiences, and this dual purpose sometimes leads to some tension but mostly works.  Lekson is a very good and engaging writer.  He has a very idiosyncratic style, which some may not find appealing, but I like it, and it definitely contrasts with the turgid prose that is more typical of archaeological publications.  The story he tells here will probably appeal to the two audiences somewhat differently; other archaeologists are likely to look through the text and notes for questionable statements to contest (and there are plenty), while lay readers are probably more likely to just take in the story without thinking too much about it.  Neither of these approaches is ideal, perhaps, but the book does adequately provide for both in an innovative way.

The structure of the book involves parallel stories: each chapter includes both one period in the history of Southwestern archaeology and one period in the actual history of the ancient Southwest as determined (primarily) by that archaeology.  Lekson tries to unify the two parts of each chapter with a common theme, which works better for some than for others but often seems a bit forced.  In general, the intellectual history portions of the chapters are a bit weaker than the archaeological portions, which makes sense since Lekson is an archaeologist rather than an intellectual historian.  Still, he does make a serious effort to evaluate the research of his predecessors and colleagues in the context of their times and the prevailing intellectual currents both within the discipline and within society as a whole.  This is more than most archaeologists are willing to attempt, and it helps put the archaeological data he uses to reconstruct the “history” of the prehistoric societies he discusses into its own appropriate context.

Building with Pro-Book Sign, Carrizozo, New Mexico

That “history” really is history, too.  This is a story focused on events, rather than adaptations, and part of the importance of Lekson’s discussion of the history of archaeology is to situate himself within that history and, in general, to distinguish what he’s doing here from what archaeologists typically do.  Basically, he’s seeking to write history rather than science, whereas most archaeological research in the US since the 1970s or s0, as he demonstrates, has sought to be science.  (Longtime readers will know that I have my own opinions on this question, and that they’re mostly in line with Lekson’s approach here.)  His version of “history” will probably seem a little over-simplistic to many actual historians, just as his account of the history of archaeology will doubtless seem simplistic to actual intellectual historians and historians of science, but for the general reader and for most Southwestern archaeologists the general point should come across loud and clear.

In general, Lekson gives the general outlines for the story of the ancient Southwest as he sees it, but he downplays some of his own more controversial ideas.  The Chaco Meridian is confined to the notes and occasional brief allusions in the text.  There are plenty of quibbles I have with some of his specific interpretations, especially about Chaco, but the overall picture he presents is probably broadly acceptable to a relatively large number of other archaeologists.  He definitely comes down on the side of hierarchy and extensive Mesoamerican influence, but local origin, for Chaco, which shouldn’t be a surprise for anyone who’s read any of his other recent Chaco stuff.  He also tries to tie everything together into a larger story, emphasizing the likely connections between developments at Chaco and among the Hohokam in Arizona, the Mimbres in southwestern New Mexico, and other Southwestern groups, as well as contemporaneous developments in Mexico and in the Mississippi Valley.  These broad-scale connections are controversial among archaeologists, but I think Lekson’s right on track in emphasizing them.

I’m not sure how well this book will work as an introduction to Southwestern archaeology for people who know literally nothing about it.  For those who know nothing about the ancient Southwest and have no intention of learning about it in great depth, this would be an entertaining and informative read.  Moving on from this to anything else written on the ancient Southwest (with the possible exception of some of Lekson’s other stuff) would be a pretty severe shock, however.  The difference in both tone and content is huge.  For people who are interested in the subject and have read one or two other books on it, however, this would be a very useful introduction to a very different way of thinking about these issues.  All professional Southwestern archaeologists should absolutely read it, not so much because they’ll learn much from it, although they might, but because it outlines a very different way of thinking and writing about the ancient Southwest that they should really be familiar with, even if they don’t want to do it themselves.

Personally, while I don’t agree with all of Lekson’s interpretations, I find this book inspiring.  Lekson is really pioneering a new way of writing the story of the ancient Southwest, and reading his version really makes me want to follow in his tracks and write my own version of the story, using his guidelines but reaching my own conclusions.  I don’t know if I’ll actually be able to follow through and write my own book, but it’s something I’ve been considering for a while now and reading Lekson’s attempt has made me more tempted than ever to actually do it.  After all, I’ve got plenty of time on my hands these days.

The Library Bar & Grill, Albuquerque, New Mexico

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Basketmaker Pithouse, Mesa Verde

The Basketmaker III period (ca. AD 500 to 750) is a very important time for understanding the prehistoric Southwest.  Maize agriculture had been introduced earlier, although exactly how early is still a matter of debate, and it was definitely well-established by the immediately preceding Basketmaker II period, but Basketmaker III saw the introduction of beans, pottery, and the bow and arrow, all of which led to major changes in the lifestyles of local agriculturists.  Residence was in pithouses, which are clearly ancestral in form (and probably in function) to the “kivas” of later sites, and while these are usually found isolated or in very small groups, there are a few known examples of large “villages” containing dozens of pithouses.  The processes that led to the formation of these sites, as well as their relationships to the more common isolated sites, are very poorly understood, but it seems pretty clear that residential aggregation in certain locations during this period set the stage for the later formation of large villages during the succeeding Pueblo I period and afterward.

Two of the largest and best-known Basketmaker III villages are in Chaco Canyon.  The better-known of these, by far, is called Shabik’eschee Village, and it is located on the lowest terrace of a finger of Chacra Mesa at the east end of the current Chaco Culture National Historical Park.  Shabik’eschee was excavated by Frank H. H. Roberts in the 1920s as part of the Smithsonian/National Geographic project led by Neil Judd.  The main focus of the project was the excavation of Pueblo Bonito, but Judd had other members of the team, including Roberts, excavate several other sites in and around the canyon as well.  Roberts published his results in 1929, and this publication has been enormously influential in shaping subsequent interpretations of Basketmaker III villages and the period as a whole.

Looking South from Peñasco Blanco toward 29SJ423

The Chaco Project in the 1970s did some additional work at Shabik’eschee, as well as at the other Basketmaker Village in the canyon.  This site, known as 29SJ423, is just south of Peñasco Blanco at the far west end of the canyon, near the confluence of the Chaco and Escavada Washes.  It is situated in a similar location to Shabik’eschee, on a lower terrace of West Mesa (but above Peñasco Blanco, which is on the lowest terrace).  Tom Windes excavated a small portion of 29SJ423 in 1975, but he and other Chaco Project personnel soon came to the conclusion that additional excavation there would not be worth the considerable effort involved.  The collections from this excavation are important, however, since they were acquired using more careful, modern methods than Roberts’s.  Similarly, a very small amount of additional excavation at Shabik’eschee in 1973 has provided important supplemental information with which to evaluate Roberts’s interpretations.

Windes and Chip Wills published an article in 1989 looking back at Roberts’s interpretations at Shabik’eschee in the light of the additional knowledge gained by the Chaco Project excavations.  They concluded that some of Roberts’s ideas, such as his proposal that the site had two discrete periods of occupation separated by a hiatus during which it was abandoned, are likely untenable, and they also concluded that the site was considerably larger than Roberts thought.  They agreed with Roberts that some of the pithouses had been abandoned and their materials were used in subsequent construction, but they saw this as more of an ongoing process related to the short use-life of pithouses and the demands of demographic processes rather than a discrete series of two occupations.  They also saw more spatial patterning in the layout of pithouses within the site than Roberts did, suggesting that the pithouses grouped into what might be family residence units, although they were quite tentative in this finding and did not use these groups as units for any subsequent analysis.

Pinyon Trees, Pipe Spring National Monument

Wills and Windes also posited a novel interpretation for the site as a whole.  Rather than seeing it as a permanent agricultural village, they saw it as a site of occasional gatherings of more mobile families practicing a “mixed” subsistence strategy of small-scale agriculture along with hunting and gathering.  In their interpretation, a small number of families inhabited Shabik’eschee permanently, while others joined them periodically to take advantage of the site’s proximity to piñon woodlands in years with bountiful piñon-nut harvests.  They based this theory on the presence of two types of storage facilities at the site: household-level storage in the antechambers associated with some but not all of the pithouses (presumably the residences of permanent residents) and community-level storage bins scattered around the site.  The idea is that occasional surpluses of corn or whatever would be stored in the bins, and the people who lived at the site permanently watched over it and protected it.  Whenever there was a plentiful crop of piñon nuts, which happens at irregular intervals in the fall, people who lived the rest of the time in scattered locations throughout the area would congregate at Shabik’eschee to take advantage of this and stay for the winter.  If conditions in the spring were good for planting, people might stay longer and plant their crops in the area, but if not they would move on to more attractive planting locations.  Other pithouse villages, such as 29SJ423, would presumably have served similar purposes, allowing periodic aggregation to take advantage of various localized resources.

This is an interesting theory, but it’s based on exceptionally thin evidence.  Wills and Windes even concede that they are spinning this whole story purely from the nature of the storage facilities at the site, and they note that there are other ways to interpret the communal bins in particular.  Instead of protecting food stores during periods of reduced occupation, they may just have functioned to protect them in general.  The shape of the bins makes it more difficult to access their contents, which Wills and Windes interpret as evidence for a sort of semi-caching, but it would also just provide better protection from the elements, vermin, etc. for the contents.  Basically, there’s just no reason from the available evidence to buy the Wills and Windes theory.

"Pithouse Life" Sign at Mesa Verde

Indeed, the assumptions behind this theory seem problematic to me.  The ethnographic comparisons Wills and Windes use to support it are mostly from hunter-gatherer societies, and indeed their model seems to imply that the residents of Shabik’eschee were basically hunter-gatherers who did some farming on the side.  Such societies exist, and may well have existed at certain times in the ancient Southwest (such as the late Archaic), but recent studies have shown with increasing certainty that heavy dependence on agriculture was widespread already in the Basketmaker II period.  Wills and Windes seem to see the Basketmaker III inhabitants of the Chaco area as just beginning to experiment with adding agriculture to a hunter-gatherer lifeway, but it’s much more likely that they were full-time agriculturalists and had been for centuries.  They did of course still do some hunting and gathering, as their Pueblo descendants have continued to do up to the present day, but while this may in some sense qualify as a “mixed” economy that shouldn’t obscure the important fact that Pueblo societies have been overwhelmingly farming-based societies since well before the occupation of Shabik’eschee.

I think this interpretation, and others like it which were popular in Southwestern archaeology in the 1980s, results in part from the enormous influence of Lewis Binford on the development of processual archaeology.  Binford’s personal research and expertise were largely on hunter-gatherer societies, and the guidelines he set forth for “archaeology as anthropology” that were eagerly followed by young “New Archaeologists” were heavily influenced by that background.  Wills and Windes cite Binford several times in this article.

Excavating the Lift Station Site in the Chaco Maintenance Yard

Be that as it may, this is an important article just in providing an updated take on the facts about Shabik’eschee, which as Wills and Windes note has been very important in the interpretation of ancient societies generally.  It contains relatively little information about 29SJ423, but it does briefly discuss this site as a comparison.  It says even less about the much more numerous isolated Basketmaker III sites in the canyon, but it notes that Chaco Project surveys identified at least 163 pithouse sites from this period.  One that they didn’t find, because it was deeply buried under the ground, was later found by the park in the course of trying to build a lift station for the septic system.  This site, informally known as the Lift Station Site, is a Basketmaker III pithouse that was excavated while I was working at Chaco.  One of the more interesting things it revealed was an apparent location for pottery manufacture.

One of the major problems with trying to understand the Basketmaker III period at Chaco is precisely that the site are typically deeply buried, so it’s hard to even know how many of them there are.  It’s clear that this was a period of significant population in the canyon, but it’s hard to tell how many sites were occupied simultaneously.  This problem is exacerbated by the difficulty of dating many of the sites.  Tree-ring dates are often hard to obtain from the scarce wood found at excavated sites, and Shabik’eschee is particularly poorly dated.  The few tree-ring dates available seem to suggest it was occupied at some point after the mid-500s, but there are no cutting dates so any greater precision is impossible.  29SJ423 did produce two cutting dates, at 550 and 557, so it seems the two villages were most likely contemporaneous.  The isolated sites are even harder to date, of course, but the Lift Station Site produced corn that was radiocarbon dated.  I don’t know the dates that resulted, but I did hear that they were earlier than was expected based on the pottery types found.

Whole Pot from the Lift Station Site

The size of the Basketmaker III occupation at Chaco, and particularly the presence of the two large villages, has important implications for understanding the subsequent history of the canyon that I think are just beginning to be realized.  The local population seems to have declined during the subsequent Pueblo I period (ca. AD 750 to 900), when people seem to have begun to move in large numbers to higher elevations where they formed some really large villages.  However, it’s not clear that Chaco was completely abandoned during this period, and recent improvements in dating the early great houses in the canyon have shown that some of them, especially Pueblo Bonito, go back further than was once thought.  Pueblo Bonito is now known to have been begun no later than 860, and the earliest part of it may date much earlier, possibly to 800 or even before.  This means that the gap between the Basketmaker III villages and the earliest great houses suddenly looks a lot smaller, and may disappear entirely.  There are pithouses under the plaza at Pueblo Bonito that may date to very early Pueblo I or even Basketmaker III, and there is a small Pueblo I occupation at Shabik’eschee that dates as late as 750.  This suggests that these two iconic sites in Chacoan archaeology, generally interpreted in very different ways, may actually overlap in occupation.  This would require some serious modifications of the ways the origins of the Chaco system are often interpreted.

Chaco had been an important place for a very long time when it started to become a major regional center around AD 1040.  It’s looking increasingly plausible, though by no means certain, that it had been continuously occupied for 500 years at that point, and even if there was a brief gap between the Basketmaker III villages and the first Pueblo I great houses it is very unlikely that is was long enough for people to have forgotten about Chaco and what had happened there.  Even if many of the people who built and/or occupied the early great houses in the 800s hadn’t been born at Chaco, they probably knew it was there long before they made it their home.
ResearchBlogging.org
Wills, W., & Windes, T. (1989). Evidence for Population Aggregation and Dispersal during the Basketmaker III Period in Chaco Canyon, New Mexico American Antiquity, 54 (2) DOI: 10.2307/281711

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Room 6, Pueblo Bonito

The “Chacoan era” is a period of about 100 years in the eleventh and early twelfth centuries AD during which Chaco Canyon was at the center of some sort of system that covered a large portion of the northern Southwest.  The exact nature and exact extent of that system are endlessly debated, but the period during which it existed is fairly well-established.  The exact dates given for the duration of the system vary among different researchers, and I’ve given various versions of them myself.  Probably the most common ending date is AD 1130, which coincides both with the approximate end of apparent construction in the canyon and the onset of a 50-year drought that is generally thought to have had something to do with the decline of Chaco.  To make it an even century, 1030 is a useful starting date for the Chacoan era, although it doesn’t actually correspond to anything special in the canyon as far as we can tell.  A better starting date might be 1040, which is approximately when the expansion of Pueblo Bonito began, or 1020, which is about when construction began at Pueblo Alto.  Using these starting dates with the hundred-year span gives ending dates of 1140 or 1120, which again are roughly equivalent to the end of major construction in the canyon.  (It’s a lot easier to date the beginnings of phenomena in the ancient Southwest than the ends of them, due largely to the reliance on tree-ring dates.)

Whenever we say the Chacoan era began, it was long after the first great houses in Chaco Canyon were built.  Indeed, the canyon had a long and probably very eventful history well before things really got going in the early 1000s.  During the 900s it may not yet have been important on as large a scale as it became later but it was definitely already a place where things were happening.  The origins of Chaco lie even earlier, however.

Type I and Type II Masonry Abutting at Peñasco Blanco

The first three great houses built in the canyon were Pueblo Bonito, Una Vida, and Peñasco Blanco.  Una Vida is mostly unexcavated and Peñasco Blanco is completely so, so the dating of them relies mainly on tree-ring sampling of exposed wood.  This has shown that these two sites probably date originally to the late 800s, with extensive expansion in the 900s.  The earliest cutting date at Una Vida is from AD 861, while Peñasco Blanco has a cluster of cutting dates at AD 898.  Both have clusters of dates in the 900s that suggest that much of the early construction dates to this period, and both also show expansion later, during the Chacoan era itself.  Beyond that, though, not much can be said about the chronology of these sites.

Pueblo Bonito is a different story.  It’s almost completely excavated, and while the excavation took place a long time ago, it left a lot more exposed wood than at most other sites.  The recent Chaco Wood Project, which sought to sample every piece of exposed wood in the canyon to develop as full a chronology as possible, had its most spectacular results at Bonito.  These were reported in part in an article in 1996 by Tom Windes and Dabney Ford, and the implications of the new dates for the architectural history of the site were more fully explained by Windes in a subsequent book chapter published in 2003.

Beams Sampled for Tree-Ring Dating in Room 227, Pueblo Bonito

To get a sense of the scale of this project, before it began in 1985 there were 163 pieces of wood from Pueblo Bonito that had been tree-ring dated.  By the time the 1996 Windes and Ford article was published, this figure had risen to 4,294.  That’s a big difference!  We now have a much better idea of when different parts of Bonito were constructed, and that has shed important light on developments in the canyon at large and their relationship to events elsewhere in the Southwest.

Before this project, Pueblo Bonito was thought to have been initially constructed in the early 900s, with some reuse of beams from earlier structures accounting for a handful of dates in the 800s.  This interpretation, expressed most influentially by Steve Lekson in his 1986 book on Chacoan architecture, was based largely on a tight cluster of cutting dates at AD 919 from Room 320 in the western part of “Old Bonito.”  The enlarged sample, however, showed that it was actually this cluster that was a fluke, and that other beams from this wing produced dates in the mid-800s that more likely represent the initial construction of this part of the site.  This seems particularly likely because the types of wood represented by these beams are largely piñon, juniper, and cottonwood, locally available species that were widely used early on, before the beginning of large-scale, long-distance procurement of large beams of ponderosa pine and other high-elevation woods.  This suggests that the beams in Room 320 which dated to 919 were probably replacement beams rather than original construction.  This block of rooms at the western end of Old Bonito was probably built around 860.

Room 320, Pueblo Bonito

Lekson thought this roomblock was probably the earliest part of the site.  As it turns out, it was even older than he thought, but evidence from other parts of Old Bonito suggests that it was not actually the earliest part.  A cluster of cutting dates at AD 891 in the northeast part of Old Bonito, which was clearly added onto the north-central part to the west of it, suggests that it was the north-central part that was actually first.  This makes sense just from looking at the plan of the rooms, actually.  This part of the site is less regular and formal in organization than the east and west wings of Old Bonito, and since it lies between them it seems logical that they would have been added on to the original central room suites.  This is a bit hard to interpret, however, since the places where these different parts of the Old Bonito arc would have come together are mostly buried under complicated later construction.

Windes suggests in his 2003 paper that the very oldest part of the site was the block consisting of Rooms 1, 2, 4/5, 6, 35, 36, 37, and 61.  None of these rooms produced wood that could be dated.  Room 6 contains a considerable amount of original wood, which can be seen today under a modern roof put on to protect it, but this is mostly cottonwood, which is very difficult to date.  As noted above, however, the use of local types of wood like cottonwood is a characteristic of very early construction at Chaco, so even though these beams couldn’t be dated they do still provide some evidence that this part of the site is very early.  The western roomblock, dating to around 860, was probably added onto this one.  This implies that the north-central block predates 860, and Windes says it is “probably much earlier” even than that (although he doesn’t explain why he thinks this).

Intact Roof Beams in Room 6, Pueblo Bonito

How much earlier?  It’s hard to say.  The earliest cutting date at Bonito is 828, from Room 317 in the western roomblock, which both Lekson in 1986 and Windes and Ford ten years later considered likely to be a reused beam.  Since the overall distribution of dates in this block suggests construction around 860, this is probably right, and it’s hard to say where the beam would have come from.  Probably not the north-central roomblock, which would probably have still been in use in 860.  Interestingly, this beam is of ponderosa pine.

The north-central roomblock could well date to around 800 or even earlier, and that brings us to an interesting point.  There are a bunch of pitstructures buried deep under later construction in what would have been the original plaza of Old Bonito; these were not extensively excavated, but they probably correspond to the room suites that make up Old Bonito and therefore date to the 800s.  There are two even earlier pitstructures, however, further south in the later plaza of the expanded Bonito.  Neil Judd, who excavated the site in the 1920s, didn’t pay much attention to them because he thought they were too early to have anything to do with Pueblo Bonito itself.  They apparently date to the Pueblo I or late Basketmaker III period.  Back when the consensus was the Bonito itself wasn’t built until 919, it made sense to agree with Judd that these pithouses were too early, but now that we know that the earliest parts of Old Bonito date well back into Pueblo I it starts to look more plausible that there is actually some continuity here.  Since Judd didn’t look very closely at the early pithouses, we have no way of dating them, which is unfortunate, but one possibility that is looking increasingly plausible is that there was no hiatus at all between the occupation of those pithouses and the earliest occupation of Old Bonito.  In that case, Pueblo Bonito as an important, inhabited location (rather than as the building we see today) might actually date back to Basketmaker III.  And, importantly, whoever lived there at that time wouldn’t have been alone in the canyon.  But that’s an issue for another post.
ResearchBlogging.org
Windes, T., & Ford, D. (1996). The Chaco Wood Project: The Chronometric Reappraisal of Pueblo Bonito American Antiquity, 61 (2) DOI: 10.2307/282427

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Train Station, Dolores, Colorado

Southwestern archaeology, especially in the Chaco area, is structured chronologically primarily by the Pecos Classification.  This system was initially worked out at the first Pecos Conference in 1927, and it was originally interpreted as a series of stages in cultural development, with the assumption that sites with similar characteristics and material culture were roughly contemporaneous.  Once tree-ring dating became available, however, it became clear that this wasn’t quite true, and furthermore that different sub-regions of the Southwest went through the stages at different times.  There have been a variety of approaches developed in the decades since to either redefine the Pecos system or abandon it.  In the Four Corners, the main approach has been to just recast the Pecos stages as chronological markers without any inherent cultural content.  The exact dates used for each stage vary by specific area and specific researcher, but here’s a rough outline of how they are often defined:

  • Basketmaker II: 500 BC to AD 500
  • Basketmaker III: AD 500 to 750
  • Pueblo I: AD 750 to 950
  • Pueblo II: AD 950 to 1150
  • Pueblo III: AD 1150 to 1300
  • Pueblo IV: AD 1300 to 1540

There’s no Basketmaker I.  The Pecos Conference attendees were unsure what, if anything, came before Basketmaker II, and they provisionally included an earlier stage in case there did turn out to be earlier sites.  As it turned out, there were, but they were sufficiently different from Basketmaker sites that they ended up being considered part of the Archaic period of hunter-gatherer societies predating the introduction of agriculture.  (Recent discoveries have begun to muddle this picture, at least for certain areas, but while not everyone still uses the term “Archaic” for the period just before Basketmaker II no one has yet begun to call it “Basketmaker I.”)

Camping at McPhee Campground for 2009 Pecos Conference

Although the stages are generally interpreted as chronological rather than developmental these days, there is still a general sense of what sorts of sites are “typical” or expected for each stage, and this has driven a lot of the variation in specific date ranges.  Basketmaker II sites are generally associated with corn and squash agriculture, a scattered settlement pattern, lots of basketry but no pottery, and the use of the atlatl.  In Basketmaker III this pattern was adjusted by the introduction of the bow and arrow, pottery, and beans, and people began to cluster in some cases into pithouse villages, although there were still many isolated hamlets in some areas.  Pueblo I was something of a transition between Basketmaker III and Pueblo II, with the first construction of significant above-ground architecture in addition to pithouses.  Pueblo II was associated with masonry roomblocks and kivas, generally organized as “unit pueblos” of a few rooms with a kiva and trash mound in front and loosely grouped into “communities.”  The height of Chaco dates to this period, and within the area of Chacoan influence these communities typically had great houses in addition to the unit pueblos but separate from them.  In Pueblo III people began to aggregate into larger, denser communities more like the “pueblos” of historic times.  The cliff dwellings at Mesa Verde and elsewhere date to this period and are the best known of these aggregated sites, but there were many others in a variety of locations.  At the end of the Pueblo III period almost all of the Four Corners area was abandoned and people aggregated further into even larger pueblos in the Rio Grande Valley and the Zuni and Hopi areas to the west, in addition to a few other areas.  The Pueblo IV period is marked by the increasing concentration of population into ever-larger sites and the clustering of these sites in particular areas separated from other clusters by uninhabited “buffer zones.”  This period also saw the apparent introduction of the kachina cult and various other novel social phenomena, and it continued until the Spanish showed up and smashed everything.

That’s the picture in a nutshell, but some periods are better-known than others.  Pueblo II and III have been particularly well-researched in the Chaco and Mesa Verde areas, although there is still plenty that remains unknown about them.  In contrast, Pueblo I was very poorly understood until the Dolores Project in the 1980s totally revolutionized our knowledge of it.  This project was a massive cultural resource management (CRM) salvage project in advance of the damming of the Dolores River and the creation of McPhee Reservoir.  At the time it was the largest CRM project ever, and it might still have that distinction.  Numerous sites in the Dolores River Valley were excavated carefully and thoroughly documented.

McPhee Reservoir from McPhee Campground, Site of 2009 Pecos Conference

It’s impossible to overstate how much our current knowledge of the Pueblo I period is based on the discoveries made at Dolores.  What the project found was that the Dolores Valley, although sparsely occupied both before and after Pueblo I, during Pueblo I contained numerous large, dense villages, most of which only existed for a very short period of time during the AD 800s.  As research continued throughout southwestern Colorado, it became more apparent that these villages were just part of the story of the incredibly dynamic Pueblo I period.  People were moving all over the place, very rapidly, and forming and dissolving villages within the space of one or two generations.  Abundant evidence for drought and conflict at certain key points during the period provided some explanation for why, but the really important thing that came out of the Dolores Project specifically was the detailed study of some of the specific villages that allowed reconstruction of their short histories with remarkable precision.

On a larger scale, it appears that the Pueblo I period involved the movement of people into higher elevations than they had occupied during Basketmaker III, followed by movement back down after 900 and into Pueblo II.  While areas with Pueblo I villages typically didn’t have substantial earlier or later occupations, many other areas (including Chaco) had major Basketmaker III and Pueblo II occupations but little evidence of use during Pueblo I.  This probably had to do with climatic changes, but there were clearly also a lot of social processes going on as well.  Since the rise of Chaco as a regional center began right after all of this, Chacoan specialists have been realizing recently that the evidence from Dolores is very important as background for understanding Chaco.

McPhee Reservoir, Dolores, Colorado

Particularly influential in shaping understandings of Chaco has been one of the Dolores villages in particular, known as McPhee Village.  Like the other Dolores villages, McPhee was founded around 840 as people began to move out of earlier villages further south around Mesa Verde and Durango.  Not everyone from these earlier villages went to Dolores (an important point), but many did, and the Dolores villages grew rapidly, only to decline just as rapidly as people moved out starting in the 870s and continuing until around 900, at which point there was only a very small remnant population in some of the villages.

The remarkable thing about McPhee Village was the presence of some roomblocks there that bore an uncanny resemblance to the early “great houses” that would arise in the San Juan Basin to the south, including at Chaco, shortly afterward.  Not all of the roomblocks were like this; most were small, linear unit pueblos typical of those in most other villages.  Two roomblocks in particular, however, known as McPhee Pueblo and Pueblo de las Golondrinas, looked astonishingly like the early form of Pueblo Bonito.  They were arc-shaped rather than linear, with two arcs making up McPhee Pueblo and Pueblo de las Golondrinas consisting of one larger arc.  (Note that “McPhee Pueblo” refers to a specific roomblock within “McPhee Village.”  The terminology is confusing.)  Furthermore, these roomblocks were made up of room suites consisting of three rooms, with one large room facing the “plaza” within the arc backed by two smaller “storage” rooms.  The “plaza” area within each arc contained pit structures presumably associated with these suites.  Again, this is much like the layout of Pueblo Bonito and other early Chaco great houses.  These roomblocks were also made largely of masonry rather than adobe, in contrast to most earlier sites as well as many other Dolores villages, which again linked them to the later Chaco sites.

Dolores Medical Center, Dolores, Colorado

A variety of studies have been done of these sites, particularly focused on what differentiated them from other roomblocks at McPhee Village.  James Potter did a study of animal remains at McPhee Pueblo and Pueblo de las Golondrinas, looking for evidence that the residents of these sites might have hosted community-wide feasts and/or conducted special rituals, either of which could have been ways for them to gain social power within the community.  Both sites contain, in addition to the standard residential pitstructures common at all sites in the village, special “oversized” pitstructures with more formal, elaborate features that could have served as special locations for feasts or rituals.  He found that McPhee Pueblo did indeed have a much higher number of different types of animal remains present, including many “non-economic” species such as carnivores and certain birds that may have had important ritual uses.  Furthermore, it had a higher proportion of rabbits than most other roomblocks, which is significant because among the modern Pueblos rabbits are often hunted communally and eaten in ritual feasts.  Interestingly, Pueblo de las Golondrinas, despite its size and the presence of an oversized pitstructure, did not have these characteristics, suggesting that its inhabitants may not have been as successful as those at McPhee Pueblo at hosting communal rituals and increasing their power.

Another take on this question comes from an analysis of ritual architecture by Gregson Schachner.  Starting from the assumption that times of significant environmental and social change, such as those that surely accompanied the rapid founding and dissolution of the Dolores villages, offer opportunities for ambitious individuals or groups to gain power and influence by taking control of ritual practices or introducing new ones, he noted that unlike some other Dolores villages McPhee Village doesn’t have a great kiva, the standard community ritual structure both before and after the Pueblo I period.  Instead, roomblocks like McPhee Pueblo and Pueblo de las Golondrinas have the oversized pitstructures that might have been used for special ritual practices that the inhabitants of those sites may have tried to introduce to their communities. Schachner assumes that these pitstructures were primarily ritual rather than residential, which I think is dubious, but otherwise his arguments make sense.  He basically sees the process as having involved certain individuals or groups having tried to introduce new rituals that gave them increased status and power in the context of the convulsions of the Pueblo I period.  Those rituals might have been adopted because they offered a new way forward during the drought that coincided with the founding of the Dolores villages in the 840s, but they might have lost their appeal as a new drought in the 880s led people in the village to reject the innovations of these would-be leaders.  As the village dissolved, construction seems to have begun on a new great kiva over the oversized pitstructure at Pueblo de las Golondrinas.  This great kiva was not completed, however, and the whole village was soon abandoned.  Great kivas continued to be a key part of the new villages further to the south that appear to have absorbed many of the people leaving Dolores after 880, but the oversized pitstructure does not seem to have continued as a recognizable architectural form.

Mac's Plumbing, Dolores, Colorado

The great house form, however, which began to proliferate in the San Juan basin starting in the tenth century, seems to have some connection to the arc-shaped roomblocks at Dolores.  Recently, a model for the rise of Chaco incorporating the insights of the Dolores Project has begun to gain increasing acceptance.  Under this model, the frustrated would-be elites from the Dolores villages moved south into Chaco and other communities and began to build similar structures to those they had lived in at Dolores.  This time, however, circumstances were better, and they were able to gain more control over their communities.  These communities were spread throughout the basin, but those in Chaco Canyon specifically eventually gained ascendancy over the others, and the Chaco Phenomenon was born.

There is a certain logic to this, and parts of it are likely true, but it’s important to note that the timing isn’t quite right for frustrated elites from Dolores to have founded the first great houses at Chaco.  The earliest parts of Pueblo Bonito are now thought to have been built by 860 and perhaps considerably earlier, while the Dolores villages didn’t start to dissolve until the 870s.  It’s quite possible that later additions to the site in the 890s and early 900s involved immigration from Dolores, and indeed it is these room suites that are particularly similar to those at McPhee Pueblo.  It’s worth considering, however, the possibility that the early history of Chaco involved people moving in from the south as well as the north, and we don’t know nearly as much about the Pueblo I period in that area.  Were there large, unstable villages with ambitious families or individuals there too, or was something totally different going on that led people to head north at the same time people were heading south from Dolores?  We can only guess at this point, but it’s important not to let our greater knowledge of developments at Dolores lead us to focus too much on it to the exclusion of other important areas.  Dolores was very important, no question, but it wasn’t the only important place at the time.
ResearchBlogging.org
Potter, J. (1997). Communal Ritual and Faunal Remains: An Example from the Dolores Anasazi Journal of Field Archaeology, 24 (3) DOI: 10.2307/530690

Schachner, G (2001). Ritual Control and Transformation in Middle-Range Societies:
An Example from the American Southwest Journal of Anthropological Archaeology, 20, 168-194 DOI: 10.1006/jaar.2001.0379

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Reconstructed Great Kiva, Aztec Ruins National Monument

Although the idea that the small round rooms that area so common at Chacoan sites are ceremonial “kivas” has been increasingly challenged recently, it is still widely accepted that the large, formal, round structures known as “great kivas” were in fact community-wide ceremonial or integrative facilities.  Even Steve Lekson agrees, and he continues to use the term “kiva” in referring to these structures even as he calls the small “kivas” “round rooms” instead.  (He also uses the term “kiva” in referring to “tower kivas,” yet another form of round structure with proposed ceremonial associations.)  Ruth Van Dyke‘s chapter in The Architecture of Chaco Canyon, New Mexico is a good summary of current knowledge about Chacoan great kivas.  The great kiva is an architectural form that predates Chaco, and it may or may not have outlasted it.  The Chacoan form is distinctive, however, and found even in areas without a long history of pre-Chacoan great kivas.  It is highly standardized in both size and features, and is one of the surest indications of Chacoan influence wherever it is found.

Floor Features of Kiva Q, Pueblo Bonito

The following features are always found at Chacoan great kivas, although their specific realization can vary a bit:

  1. Four post holes, arranged in a square, to support the beams or columns that hold up the roof.  The holes may be either round or square.  Generally the columns themselves would be huge wooden beams, stubs of which have sometimes been found in the post holes during excavation.  Sometimes, such as in the great kiva at Aztec Ruins, square masonry columns, possibly with small poles in them, would be used instead.  It’s apparently not totally clear if the use of square rather than round post holes necessarily indicates the use of pillars rather than beams, since the beams would typically be held in place by shale and this could be done in either a square or a circular space.  When beams were used, they were supported at the bottom by several stacked stone disks, presumably to distribute the weight.  Offerings of turquoise and other valuables were often found in the beam holes, apparently placed during construction.
  2. Around the circumference of the kiva is a bench, sometimes doubled.  These benches were often refaced with new masonry, sometimes in connection with more general renovation of the kiva features and sometimes not.
  3. There is typically a series of wall niches around the circumference of the chamber, above the bench.  These vary in dimensions and number, but there are usually about 30 of them, especially in later great kivas.  Sometimes there is more than one series of niches at different levels, as at Casa Rinconada.  The purpose of the niches is unclear; some of them had offerings sealed into them, but these may have been construction offerings rather than indicating anything about post-construction use.
  4. Entrance is from a staircase leading down from an antechamber.  There would probably have been a smokehole in the roof as well, but it is unclear whether there would have been a ladder providing entrance through the roof as was the case in smaller round rooms.  An intact great kiva roof has never been found, which is unsurprising since the roofs would have been enormously heavy and very likely to cave in once the structure was no longer maintained.  The antechamber is on the north side in most cases.  Kiva Q at Pueblo Bonito has an apparent staircase and antechamber on the south side instead, but Van Dyke suggests that this may have been an error of reconstruction.  She doesn’t go into any more detail about this, however, and it’s unclear what the implications are if the room on the south side of Kiva Q is not an antechamber.  Casa Rinconada has antechambers with staircases on both the north and south sides.
  5. Along the central north-south axis, slightly offset to the south from the center point, is a firebox.  This is usually a masonry cube with a circular or oval firepit in it.
  6. Just south of the firepit there is a deflector.  This is a common feature in small kivas, which usually have a ventilation shaft on the south side, but since great kivas don’t have ventilation shafts and usually have their entrances on the north side it is unclear how useful this deflector would have been in practice.  Assuming there was a smokehole, a great kiva was big enough that it’s unlikely ventilation would have been a major concern.
  7. Attached to the two southern postholes on the north side, and sometimes running all the way to the northern postholes, there are two rectangular masonry “vaults.”  They are usually but not always subterranean.  The function of these is unclear.  Some have claimed that they are “foot-drums,” which would have had boards on top of them and people dancing on them, but not everyone accepts this interpretation and I don’t find it very convincing.  Small kivas sometimes have a single subfloor vault on one side of the firepit, but it is unclear if there is any connection between that type of feature and the much more formal vaults of great kivas.

These are the basic features that are repeated again and again at Chacoan great kivas.  Relatively few have been excavated, but all of those that have show these same features with minor variations.  Van Dyke provides a comprehensive list of the known great kivas at Chaco.  There are 21 of them, of which 11 have been excavated.  Ten of these are associated with the great houses Pueblo Bonito (4 great kivas), Chetro Ketl (3), and Kin Nahasbas (3).  (Note that Van Dyke is counting remodeled versions of earlier great kivas separately here.)  The only “isolated” great kiva to be excavated is Casa Rinconada.  It is also the largest excavated great kiva in the canyon at 19.5 meters in diameter, although it is not the largest excavated great kiva (the one at Village of the Great Kivas, a Chacoan outlier on the Zuni Reservation, is 23.7 meters in diameter), nor is it the largest great kiva in the canyon (the unexcavated northwest great kiva at Peñasco Blanco is 23 meters in diameter).

Casa Rinconada, Looking North

Van Dyke explicitly cautions her readers to be careful about the possibility of overemphasizing the importance of Rinconada just because it is so well known, and this is an important warning.  It does appear that Rinconada is unusual among all known great kivas in several ways, including the two antechambers and the “secret tunnel” leading from a back room of the north antechamber to a subsurface round enclosure around the northwest posthole.  It is also positioned in a very significant location, across from Pueblo Bonito, and there may be astronomical alignments encoded into it.  However, it is important to note that like the other great kivas at Chaco that are visible today, Rinconada has been substantially reconstructed.  In general Chaco has had a much lighter touch with reconstruction than many other parks, but great kivas, which are typically found in a substantially reduced state with large v-shaped breaches in the upper walls, are an exception.  Kivas A and Q at Pueblo Bonito as well as Casa Rinconada have all been built up to what their excavators considered a reasonable approximation of their original condition.  The great kiva at Aztec, of course, has been completely reconstructed to give an impression of what it might have looked like, and while there was apparently once talk of doing something similar at Casa Rinconada nothing ultimately came of it.

In addition to the excavated great kivas, there are ten unexcavated ones at Chaco.  It is hard to tell much about these, since they are basically just big recessed circles in the ground, but they are generally at least in the same size range as the excavated examples and can probably be assumed to be similar.  There may well be additional unknown ones, either associated with great houses or isolated.  It is particularly likely that early great kivas would not be apparent on the ground, since they are generally smaller than later ones and the excavated examples (or possible examples) all come from within early great houses where they are often overlain by later construction.

Northwest Great Kiva at Peñasco Blanco

The known unexcavated great kivas associated with great houses include two at Una Vida, one at Hungo Pavi, and four at Peñasco Blanco.  There are also three “isolated” great kivas, all of them at the east end of the canyon: one in Fajada gap, one on the south side of the canyon across from Wijiji, and one in a side canyon at the foot of Chacra Mesa below the Basketmaker III village known as Shabik’eshchee.  As noted above, the northwest one at Peñasco Blanco is huge, probably the largest at Chaco.  The one in Fajada gap appears to be about 20 meters in diameter, which puts it in the same size range as Casa Rinconada, although the difficulty of measuring diameter precisely with unexcavated great kivas makes it impossible to say if it is actually bigger than Rinconada or not.  One interesting thing about these isolated great kivas is that they are all on the south side of the canyon, as is Casa Rinconada.  This contrasts with the tendency of great houses to be on the north side and provides some support for the idea that the great kiva is conceptually separate from the great house and has its own history as a form.  It’s hard to say how to interpret this in the context of the postulated attempt by great-house elites to incorporate great kivas into their great houses as a way to legitimize their authority, which Van Dyke proposes as an explanation for why most great kiva construction at great houses didn’t take place until the mid-1000s.

And, indeed, early great house construction does seem to be notably bereft of great kivas.  Or does it?  Tenth-century “great kivas” are in fact postulated at Pueblo Bonito, Una Vida, and Kin Nahasbas, and Van Dyke includes them on her list, but it is unclear whether they really “count” as great kivas.  They are smaller than the later versions, which may just be because they are older.  They are also poorly documented, however; the ones at Pueblo Bonito and Kin Nahasbas have been excavated, but records about them are scarce and scanty.  The one at Pueblo Bonito is about 10 meters in diameter, which Van Dyke considers “within the range known for domestic pitstructures,” and furthermore it lacks postholes for roof support beams but does appear to have pilasters on its bench, which implies a roofing system like that of small kivas.  Since the roofing system is one of the most consistent features of classic Chacoan great kivas, this is a major strike against great kiva status for this one.  However, it’s possible that the specialized roofing system for later great kivas was an innovation to handle the large size of the ones built from the mid-1000s on, and that earlier structures with “regular” kiva roofs may have had “great kiva” functions in the 900s.  (This reminds me that I should do a post on small-kiva roofing, which is an interesting and surprisingly contentious issue.)

Kin Nahasbas from Una Vida

Evidence that the specialized roofing system for great kivas was already in place in the 900s comes from the early “great kiva” at Kin Nahasbas, which was more thoroughly excavated than the one at Pueblo Bonito.  It underlies the two later great kivas, which had classic great kiva features.  Its own features were largely obscured by the later construction, but it does appear to have postholes.  It couldn’t be dated directly, but the excavators concluded that it was probably associated with the tenth-century greathouse behind it.  This implies that there was at least one great kiva this early, but that the one at Pueblo Bonito was not one.  Interestingly, the diameter of this great kiva was only 7 meters, making it smaller than the Pueblo Bonito example and suggesting that size isn’t everything when it comes to great kivas.

The early great kiva at Una Vida is very poorly known and may not exist at all.  There is certainly another, later great kiva at the site.  Van Dyke refers to William Gillespie’s account of Una Vida’s architecture in Steve Lekson’s Great Pueblo Architecture of Chaco Canyon, New Mexico as the source for the idea that there is a great kiva associated with the early-tenth-century construction there, but Gillespie is very vague about the basis for his speculation that such a great kiva existed, and says only that “surface evidence is inconclusive.”  Van Dyke lists the diameter of this postulated great kiva as 17 meters, which is remarkably large for such an early structure and only slightly smaller than the later great kiva, which is much more obvious and has a diameter of about 18 meters.  Una Vida is a very confusing and poorly understood site, so the lack of clarity regarding its great kiva(s) is not really surprising.

The only other early great house, in addition to these three, at Chaco is Peñasco Blanco.  It apparently has four great kivas, none of which has been dated.  It’s quite possible that one or both of the two great kivas in the plaza dates to the 900s, but neither has been excavated.  It is also possible that there are additional early great kivas either underlying the later ones or elsewhere in the site.  The number of apparent great kivas is one of the many reasons I think this site is likely much more important to Chaco than is usually appreciated.  It is both one of the earliest sites at Chaco and one of the largest, and it may have served as an important connection to the communities downstream on the Chaco River, where many of the early great houses were, as well as with the Chuska Mountains beyond.  Van Dyke has little to say about it in this chapter, which is understandable since the great kivas are unexcavated (as is the rest of the site).

Snow at Kiva A, Pueblo Bonito

The upshot of all this is that there probably was at least one great kiva built at Chaco in the 900s, and there may have been more, but it does seem to be true that great kiva construction increased dramatically after around 1030.  This is the same time that a lot of other changes were happening in the canyon, including massive construction projects of various sorts at several great houses, and it is probably the time when Chaco first became the regional center for the San Juan Basin (though it had likely been an important center for a long time).   Van Dyke argues that part of this was the appropriation of the great kiva form, which in previous times had been particularly common in communities to the south, by emergent local elites attempting to legitimate their increasingly hierarchical authority and control over periodic regional gatherings in the canyon that were beginning to draw pilgrims from throughout the Basin (and perhaps beyond).  In another article she argues that this process was part of a “tipping point” or “qualitative social transformation” that changed a predominantly egalitarian society into a more hierarchical one.  In this context, the use of great kivas may have been an attempt to establish links with the past by incorporating an old, traditional architectural form into the new and potentially threatening form represented by the great house.  I’m not sure I buy this entire story, but I think at least parts of it are likely true and it’s certainly thought-provoking.

Great Kiva at Lowry Pueblo, Colorado

Wherever they came from and whenever they became part of the Chacoan architectural repertoire, by the height of the Chacoan era great kivas were among the most standardized parts of the highly standardized Chacoan “system,” whatever it was.  There are plenty of puzzles remaining about them, as is true with most everything associated with Chaco, but regardless of whether we are ever able to answer all the questions they pose they are still among the most impressive achievements of this very impressive society.
ResearchBlogging.org
Van Dyke, R. (2008). Temporal Scale and Qualitative Social Transformation at Chaco Canyon Cambridge Archaeological Journal, 18 (01) DOI: 10.1017/S0959774308000073

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Durango, Colorado

The best-known of the various instances of alleged cannibalism in the prehistoric Southwest are a set of several that occurred around AD 1150 in the area around the modern town of Cortez, Colorado.  There are also scattered examples of similar assemblages dating to both before and after this and located both in southwestern Colorado and elsewhere, but most of them are not as well documented and they are therefore not easily comparable to the well-known assemblages.  One exception, so far the only known example of possible cannibalism dating to the period in the late thirteenth century when the Four Corners region was abandoned, is Castle Rock Pueblo at Canyons of the Ancients National Monument west of Cortez.  Earlier assemblages, in particular, are very rare, and the few known are generally not very well documented at all.  Cannibalism has thus generally been discussed in the literature as something that appears rather suddenly in the Southwestern archaeological record around 1150, perhaps indicating Mesoamerican influence that may or may not have had something to do with the rise and fall of the regional system centered on Chaco Canyon between about AD 1030 and 1130.  There have been some scattered references in the literature to earlier instances, but without good documentation they have not gotten much attention compared to the later ones.

That may now change, however.  An article published very recently reports on an astonishing assemblage recently documented in detail at Sacred Ridge, part of Ridges Basin south of Durango, Colorado (east of Cortez).  This site dates to around AD 700 to 800, during the Pueblo I period.  As part of salvage excavations in preparation for a reservoir project in the basin, archaeologists discovered one of the largest assemblages of intensively processed human remains known from the Southwest.  At least 35 people were represented in the assemblage, although the actual number present is exceptionally difficult to determine because the remains were fragmented to an enormous degree even compared to other heavily processed assemblages.   The ages of identifiable individuals ranged from infancy to adulthood.  The conditions of the deposition of the remains indicates that most were processed, possibly in connection with cannibalism, then dumped into one of the residential pithouses at the site.  Several artifacts found associated with the remains tested positive for human hemoglobin and/or myoglobin, indicating that they had come into contact with human blood and/or muscle tissue.

Francisco's Restaurante y Cantina, Durango, Colorado

This is a very large assemblage.  The well-documented assemblage at site 5MT10010 at Cowboy Wash, for example, consisted of only 7 individuals, and the other three sites in the Cowboy Wash community that have been excavated (all of which also showed evidence of cannibalism) ranged from 2 to 13 individuals.  Castle Rock had at least 41 individuals, but that was a large, aggregated community from a later period when the regional population was both larger and more concentrated in aggregated sites.  Finding 35 people killed at a Pueblo I village is extraordinary.

So who were these people?  The circumstances of the assemblage suggest that they were probably the inhabitants of the Sacred Ridge site, which contained several residential pithouses and constituted a relatively large portion of the overall Ridges Basin community.  Biometric analyses of the remains suggested that the individuals in the assemblage were both related to each other and distinct from the other people in the community.  This raises the possibility that they were recent immigrants who had attempted to move into the area, perhaps at a time when environmental conditions were difficult and some parts of the region had become less suitable for habitation, forcing their inhabitants to move into already-occupied areas where the local residents may not have been friendly.  This is similar to what some have proposed for Cowboy Wash, where ceramics indicate that the residents had strong ties to the Chuska Mountain region to the south and may have been recent immigrants into an area where they were not welcome.  The early AD 800s, when the Sacred Ridge massacre apparently occurred, does indeed seem to have been a time of difficult environmental conditions, as was the mid-1100s when the well-known cannibalism events such as the one at Cowboy Wash occurred.  The migration hypothesis thus seems fairly plausible to explain Sacred Ridge.

Railroad Station, Durango, Colorado

Not so fast, however.  In addition to doing the biometric analyses, the researchers in this case also did strontium analyses of the tooth enamel found in the assemblage.  Strontium isotope analyses can be used to determine where a person (or a tree) lived, which makes this type of analysis a useful way to directly test migration hypotheses.  Tooth enamel has a strontium ratio that reflects where a person lived as a child, since enamel is preserved throughout life after initially forming in childhood.  The strontium ratio of bone, on the other hand, reflects where a person lived shortly before death, since bone cells are continually being replaced throughout life.  In this case only tooth enamel was tested, but I’ve seen other studies comparing tooth and bone enamel to determine if a person lived in the same place at the beginning and end of life, which is just about the best way to test a migration hypothesis that I can imagine.  In the case of Sacred Ridge only tooth enamel was analyzed for some reason, but it still provides a way to determine if the individuals at Sacred Ridge had grown up in the Ridges Basin area or had moved at some point in their lives from somewhere else.

What the analysis showed was that all the analyzed individuals had likely grown up either in the immediate Ridges Basin area or nearby.  None could be conclusively identified as having grown up anywhere else.  This effectively falsifies the immigration hypothesis and requires a different explanation for the massacre.  It appears that the people who lived at Sacred Ridge were both local to Ridges Basin and distinct from the other inhabitants of the area, which the authors interpret as an “ethnic” difference.  They point to a variety of other indications in architecture and material culture suggesting that the area was quite diverse ethnically during this period, and they argue that the massacre represents ethnic violence within the community during a period of environmental deterioration likely leading to social stress.  The inhabitants of Sacred Ridge appear to have had greater access to large game animals than other members of the community, which may indicate that they were relatively well-off compared to others, who may have become resentful when times turned bad and taken out their frustrations through intensive violence, possibly involving cannibalism, which may have been so intense in part as an attempt to erase the identity of the victimized group.  The authors run through and discount a number of other explanations that have been offered for cannibalism assemblages, including warfare, social control, starvation, and witchcraft execution.  They reject these based on specific criteria they identify as the plausible archaeological correlates of each theory.  The specific correlates they offer strike me as dubious, and they do acknowledge that their “ethnic violence” theory is not necessarily incompatible with some of the others, but the approach is interesting.

Gaslight Theater, Durango, Colorado

There has been a recent trend in Southwestern archaeology toward trying to reconstruct ethnicity in the archaeological record, and there is an increasing sense that the Southwestern past may have been much more diverse ethnically than archaeologists have often assumed.  This paper takes that trend in an interesting direction by combining it with the contemporaneous trend toward greater interest in violence and warfare in the prehistoric Southwest.  The authors suggest that some of the later cannibalism assemblages might be profitably reexamined with the ethnic violence idea in mind, which is a good idea.  That said, “ethnicity” is a problematic concept when it comes to archaeological data, which is necessarily material in nature and not necessarily reflective of such an abstract concept.  It would be unreasonable to expect a short paper like this to address the issue at length, of course, and it appears that other publications from this project deal with it in more detail.  The innovative use of biodistance and strontium analyses to address these issues is a worthwhile development regardless of whether the trends identified correspond to ethnicity, however, and this paper makes for a very interesting contribution to the literature on violence and cannibalism in the Southwest that may require some adjustments to existing theories.
ResearchBlogging.org
Potter, J., & Chuipka, J. (2010). Perimortem mutilation of human remains in an early village in the American Southwest: A case for ethnic violence Journal of Anthropological Archaeology, 29 (4), 507-523 DOI: 10.1016/j.jaa.2010.08.001

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Second-Story Door, Pueblo Bonito

In comments to the previous post, john barton asked:

I’ve been many times in 20 years to chaco and read much and I’ve been forming a blasphemous opinion; what makes pueblo bonito the greatest of the great houses? Assuming all the other great houses were controlled by different entities even while sharing the same religion, why should there have been no successful challenges for bonitos status or position?

I responded, but I think this issue is actually important enough for a post.  I think john is quite possibly on to something, for reasons explained in my response, but here I want to talk about a slightly different way to look at the question of Pueblo Bonito’s uniqueness.  In my response I said that in my view the main thing that makes Bonito the greatest of the great houses is that it’s the best known and most thoroughly excavated.  There are really two parts to this.  On the one hand, the fact that so much is known about Bonito from the extensive excavations there and so little is known about other great houses means that all interpretations of Chaco are necessarily skewed by an overemphasis on Bonito and an underemphasis on the other sites.  The importance of this skew is impossible to tell, of course, because it depends on what the actual nature of the Chaco system was and what the roles of the different great houses were within it, which are basically unknowable with the information we have now.  So in that sense, Bonito is the “greatest” of the great houses just because we know more about it than we know about any of the others, and it quite possibly was not actually the greatest at the time.  In other words, the Bonito-centric nature of current models of the Chaco system could just be due to the historical accident of choices about where to excavate first, and Bonito may not actually have been the greatest of the great houses at the time.

Great Kivas A and Q, Pueblo Bonito

In another sense, though, Bonito really is the greatest of the great houses regardless of whether or not it was the greatest when it was in use.  This is precisely because it has been so extensively excavated and left open for visitors to see.  It’s really a very impressive site, and the visual impact of seeing it and wandering through its huge maze of rooms is one of the highlights of a visit to Chaco.  Because none of the other great houses have been been excavated and left open to that extent, they can’t possibly have the same effect on visitors despite.  They’re all impressive, of course, but the unexcavated and less-excavated ones are not impressive in the same way as Bonito.  The only other great house that can be experienced in anything like the same way is Aztec West, which was also extensively excavated and left open.  It’s bigger than any other great house except Pueblo Bonito and Chetro Ketl, but it is smaller than those two, and less of it is open to the public than is the case at Bonito.  It’s also somewhat less impressive just because the setting of the Aztec complex is much less striking than Chaco Canyon.

Tour Group at Back Wall of Pueblo Bonito

Back when I was giving tours of Pueblo Bonito, I began to get tired of it after a while, and I would think it was a bit overrated and that the other sites should get more attention.  I, of course, had been reading about all these sites and was interested in them based on that, and it took me a while to realize that for most visitors they’re just not going to have the same effect as Bonito.  All the sites at Chaco are worth seeing, but once I realized just how different Bonito is from all the rest I began to heavily emphasize it when advising people about what to see during their time in the park.  Places like Una Vida and Pueblo del Arroyo are definitely interesting, but I think for most visitors they’re a lesser priority, and rightly so.  Pueblo Bonito is what people come to Chaco to see.

Southeast Corner of Pueblo Bonito

When you look at it that way, it doesn’t actually matter if Bonito was the most important of the great houses in the eleventh century (or the tenth, or the ninth).  It’s the most important of the great houses now, because it’s the one that impresses people enough to draw them to the canyon from all over the world.  It’s the most impressive not because it’s the biggest, although it is, nor because it was at the center of the Chaco system, although it probably was, at least at the height of the system in the late eleventh century.  It’s the most impressive because it’s the only one you can actually walk through and experience personally.  It is of course largely because it’s the biggest of the great houses that it was excavated early on and left open as an exhibit for visitors to see, so in that sense it is the greatest of the sites because it (probably) was the greatest of them originally.  Even if a new, bigger, more important great house were somehow discovered tomorrow, however, it would not displace Pueblo Bonito as the most important of the great houses to visitors today, because there’s no way it would be excavated and left open the way Bonito has been.  Archaeology has changed over the past century, as has Park Service policy.  Pueblo Bonito is still there, though, open and accessible, and it will remain so for at least the near future.

Entrance to Pueblo Bonito with Snow

As I explained in my response to john, I suspect that Pueblo Bonito may well not have always been the most important of the great houses, although I find it most plausible that any shift of influence would have been to increase rather than diminish Bonito’s role over time, at least up until the decline of the canyon and the probable shift of the system to Aztec.  Understanding the changing dynamics of the Chaco system over time is, I think, a very important part of understanding the system in general, and one that has been largely neglected by most research, although this is starting to change.  None of that matters much for the average park visitor, though, who will remain most impressed by the stunning remains of Pueblo Bonito from the period of its height.  Whether there were other great houses that were even more impressive at that time is a rather abstract question when the grandeur of Bonito is right there, and whether earlier versions of Bonito were less important than other sites at some earlier time is even more abstract and immaterial.  It’s Bonito that people see, and they are impressed by it.  That’s a core reality that I think those of us who tend to delve deeper into the world of Chaco research can easily forget.  It’s important, though, and an occasional reminder of it is a useful reality check.

Old Bonito from Kiva Q

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Novitski Hall, University of New Mexico School of Dentistry, Albuquerque, New Mexico

I’ve recently been discussing stable isotope analysis as a way to directly determine dietary practices from skeletal evidence, and that is certainly a powerful tool in learning about past societies, but there are some drawbacks to it.  Like all complicated laboratory procedures, it’s expensive, and it has the additional problem of being destructive.  If it’s done right, it only requires a small amount of bone, but it does involve destroying that bone in the course of analysis, which puts it in tension with recent political trends away from invasive and destructive types of research.  It is therefore good to have additional ways of evaluating dietary practices, despite the enormous potential of isotope studies.

One such line of evidence is much more low-tech, and quite simple, as well as being non-destructive.  It starts from the widespread recognition that different types of diets have different and readily detectable effects on teeth.  Specifically, diets high in carbohydrates tend to result in significantly more dental caries (cavities) than diets higher in proteins and fats.  A variety of factors are involved in determining the rate of caries in a given individual, including the form of the teeth and the presence of caries-resistant minerals such as fluoride in the environment, but diet is one important factor and the one that can most easily account for differences between populations and societies in the rate of caries.  The way this works is that diets rich in carbohydrates, especially refined carbohydrates such as ground meal or flour which stick to the teeth more easily, result in buildup of plaque that certain bacteria in the mouth feed on.  Those bacteria then release waste products including lactic acid, which eats away at tooth enamel can causes caries.  Fats and proteins also cause plaque buildup, but the bacteria don’t feed on this plaque, and it tends to be less acidic and therefore less conducive to caries formation.

The implication, then, is that societies that are dependent on agriculture, in which people eat large amounts of carbohydrates, will show much higher rates of caries than hunting and gathering societies in which people eat more fats and proteins.  This has indeed been confirmed by observation of caries rates in numerous contemporary and prehistoric populations.  There are some cases in which hunting and gathering populations can have relatively high rates of caries, such as a heavy dependence on gathered resources that are high in carbohydrates, such as acorns and pine nuts, but in general the difference between foragers and farmers is quite clear and can be used to determine to what extent a given prehistoric population depended on agriculture just by looking at their teeth.

Durango Herald Offices, Durango, Colorado

One relatively recent study looking at this issue in the context of the Southwest is by Karen Gust Schollmeyer and Christy Turner.  Turner is best known in the Southwest for his controversial ideas about cannibalism, but he has also had a longstanding interest in dental studies which I’ve discussed before.  This paper looks specifically at the dispute over the timing of agricultural dependence in the Southwest and whether it arose at the same time as the “Pithouse to Pueblo Transition” between the Basketmaker III and Pueblo I periods, generally dated to around 750 AD.  The hypothesis Schollmeyer and Turner tested is that the Basketmakers had a mixed farming and foraging economy with relatively little dependence on agriculture but that later Pueblo populations were heavily dependent on farming.  This predicts that Pueblo populations should have substantially more caries than Basketmakers.  The sample they used to test this was a large collection of human remains from various sites in southwestern Colorado, mostly in the Durango area and the La Plata Valley, in the collections of the Harvard Peabody Museum and the American Museum of Natural History.  Since these were mostly excavated before 1930 and information on their exact origin and time period is often vague, Schollmeyer and Turner grouped them into just two groups, Basketmaker and Post-Basketmaker, and ran a series of statistical tests on the number and placement of caries in each group.

They found that there was basically no difference.  Both groups had very high rates of caries, whether measured as total number of carious teeth, total number of carious teeth and teeth that fell out during life (which often results from caries), or total number of individuals with carious teeth.  Statistically most of these were indistinguishable from each other, although it’s important to note that this can’t be considered a truly random sample and statistics drawn from it shouldn’t be taken too literally.  Comparisons of caries on specific types of teeth and on different parts of teeth also showed high rates in both groups.  There were no significant differences regarding types of teeth.  There was a significant but weak difference in parts of teeth, with the later individuals having more caries on the parts of the teeth facing other teeth rather than facing outward.  There was also a similarly significant but weak difference in the number of individuals with caries, which was lower in the later group, implying more caries per person with caries than in the Basketmaker period, since the overall number of carious teeth was not different.  I don’t think too much should be made of either of these differences, given the nonrandom nature of the sample, and Schollmeyer and Turner are properly cautious in interpreting them.  They do make the interesting suggestion, however, that if there is anything to these differences they may imply differences in processing of maize over time, with later groups processing it more efficiently and intensively, using more effective tools, perhaps in response to increased populations.  They further suggest that this may be behind some of the dispute in the literature over the timing of dependence on agriculture, since some of the evidence put forth as showing a late date, coincident with the Pithouse to Pueblo Transition, is based on the use of larger and more efficient grinding tools.  This is all pretty speculative, and I don’t think it’s really any more likely than the alternative explanation that the significant differences are just statistical noise, but it’s an interesting thought.

Railroad Bridge, Durango, Colorado

Overall, this evidence supports the other recent studies showing that Southwestern populations seem to have been dependent on agriculture by at least as early as the Basketmaker II period.  It’s therefore not exactly groundbreaking, but it is useful to have as many lines of evidence as possible brought to bear on important questions like this, especially when most of them seem to point in the same direction.
ResearchBlogging.org
Schollmeyer, K., & II, C. (2004). Dental Caries, Prehistoric Diet, and the Pithouse-to-Pueblo Transition in Southwestern Colorado American Antiquity, 69 (3) DOI: 10.2307/4128407

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